DESCRIPTION: (Principal Investigator's Abstract) Botulinum A toxin has emerged as a useful drug for treatment of focal dystonias. The major problems with this approach are so that some patients develop antibodies to the drug, and almost all would like to see it last longer after each injection. In this project we will develop and test in animals and humans the effect of botulinum toxins B, D, E and F on eyelid and extraocular muscle function, to determine: 1) if patients who have become resistant to type A botulinum toxin can be helped by other types; 2) if these toxins have different effects than the currently used type A toxin; 3) if toxins are synergistic when used together, having either greater effect or greater duration of action than when used singly; 4) if combinations of toxins are less antigenic than individual toxins.